Extraction of resinoids from St. John's wort (Hypericum perforatum L): I. Efficiency and optimization of extraction

Abstract

The extraction of resinoids from St. John's wort (Hypericum perforatum L) was studied in a series of two papers. In the first part, the effects of the operating conditions on the yield of resinoids (total extract) were analyzed, while the mathematical models of extraction kinetics were compared in the second one. The extraction was carried out using an aqueous solution of ethanol (70 and 95 % v/v) at a hydromodulus (plant material to solvent ratio, w/v) of 1:5 or 1:10. The plant material was disintegrated and divided into three fractions (mean particle size: 0.23, 0.57 and 1.05 mm). The temperature was 25, 50 or about 80°C (boiling temperature). A higher yield of resinoids was obtained when the plant material of greater disintegration degree (0.23 mm) was treated with 70% v/v aqueous ethanol solution at higher hydromoduli (1:10) and temperatures (80°C). The effects of the operating factors on the yield of resinoids were estimated by using both the full factorial experimental plan 24 and artificial neuronic networks (ANN) of 3-4-1 topology. Of the two methods, the ANN one was found to be advantageous because of its capability of estimating the yield of resinoids in the whole range of the applied operating conditions

Optimization of the Solid-Liquid Extraction Process of Phenolic Compounds from Mulberry Fruit

“…The most likely mechanism of action of ultrasonic extraction is intensifying mass transfer and easier penetration of the solvent into the cells of the plant material. In the classical maceration normal mechanism of diffusion through the cell walls is occurred, and therefore this process requires a much longer extraction time (Milenovic et al, 2002).…”

Comparison of Box-Behnken, Face Central Composite and Full Factorial Designs in Optimization of Hempseed Oil Extraction by n-Hexane: a Case Study

“…By statistical optimization techniques, the influence of the extraction process variables on the yield of desired extractive substance(s) is analyzed through a smaller number of experiments, which reduces greatly laboratory work and reagent consumption. For the optimization of liquid-solid extraction processes, the response surface methodology (RSM) is usually applied in combination with the full factorial design (FFD) [1][2][3], central composite design (CCD) [4][5][6][7][8][9][10][11] or Box-Behnken design (BBD) [12][13][14] serving for the data collection. The Plackett-Burman design followed by either CCD [15] or BoxBehnken design [16][17][18] has also been applied in optimizing liquid-solid extraction processes.…”

Kinetics of ultrasonic extraction of extractive substances from garden (Salvia officinalis L.) and glutinous (Salvia glutinosa L.) sage

“…The kinetics of extraction process of bioactive substances from plant materials has most often been modelled using the unsteady diffusion through plant material [7], the film theory [8,9] and the empirical equation of Ponomaryov [7,10]. These models are reviewed in Table 1; derivation of model equations can be found elsewhere [9].…”

“…These models are reviewed in Table 1; derivation of model equations can be found elsewhere [9]. The models are based on the two-stage extraction mechanism and all three are two-parametric.…”

“…One parameter characterizes the washing stage (so called washing coefficient) and the second one characterizes the slow extraction (so called slow extraction coefficient). In the case of extraction from arial parts of St. JohnÕs wort (Hypericum perforatum L.), the kinetic model based on the film theory was recommended for modelling the extraction process as fitting the experimental data satisfactory, being physically based and relatively simple [9]. No kinetic model for ultrasonic extraction has been found in the literature.…”